A mass "war grave" containing the skulls of 45 people dating back to Roman times has been uncovered as work begins on a new road being built to a 2012 Olympic venue.

Archaeologists made the discovery while carrying out a dig on the site of the new £87 million relief road to Weymouth, Dorset - the sailing venue for the forthcoming games which was visited by the Queen and Duke of Edinburgh today.

The burial pit on nearby Ridgeway Hill has been found to contain various skeleton pieces including 45 skulls.

David Score, project manager for Oxford Archaeology, said: "We have found a remarkable burial pit.

"We have counted 45 skulls so far, these are in one section of the pit, and several torsos and leg bones in separate sections of the pit.

"It is rare to find a burial site like this one. There are lots of different types of burial where skeletons may be aligned along a compass axis or in a crouched position, but to find something like this is just incredible.

"It's very early days, but so far, after a visit to the site by our head of burial services, the skulls appear to be predominately those of young men.

"At the moment we don't fully understand how or why the remains have come to be deposited in the pit but it seems highly likely that some kind of catastrophic event such as war, disease or execution has occurred."

Dorset County Council's head of highways Andy Ackerman said: "It's standard practice for major schemes to ensure that archaeological investigations are fully undertaken and it is also written into the planning conditions for such projects."

Archaeological finds from the Weymouth relief road will be offered to a Dorset museum after the analysis work has been completed and the public have been asked to stay away from the relief road site.